Hi folks.

87 740T, 260,000 km. I just changed two turbo hoses (airbox to turbo and turbo to intercooler). Impeller looked fine, with little play, and no more oil being thrown around than expected. Car runs fine now.

However, my stock turbo gauge is giving me some strange readings. Before the change, it typically went from about 9:30 to 2:30. Now, it still makes it to about 2:30 at full throttle, but if you let off the throttle, the needle plummets to the bottom of the gauge. It will creep up slowly if you coast, and jump up normally if throttle is applied. Aside from that, the gauge seems to work normally. What could be causing such dramatic increase in vaccuum as I let off the throttle, and how could changing the hoses have affected this without equally affecting the reading on the positive pressure side?

Any ideas welcome. Thanks, as usual.

RA